July 18, 2024

Lukmaan IAS

A Blog for IAS Examination



THE CONTEXT: Tropical cyclones, characterized by strong winds, heavy precipitation, and storm surges, pose significant threats to coastal communities and infrastructure. The intensification of these storms, fueled by global warming, has led to the emergence of cyclones with wind speeds surpassing the existing Category 5 threshold.


  • This necessitates the consideration of a new category, Category 6, on the Saffir-Simpson (SS) hurricane wind scale.

Tropical Cyclones:

  • Tropical cyclones form over warm tropical ocean basins with sea surface temperatures exceeding 26.5°C.
  • They are prevalent in regions such as the North Atlantic, East Pacific, West Pacific, South Pacific, and the Indian Ocean.
  • The Western Pacific basin is particularly active, accounting for a significant portion of global tropical cyclones.
  • However, the North Indian basin, while contributing a smaller share, remains highly vulnerable to cyclone impacts.

Saffir-Simpson Hurricane Wind Scale

  • It was introduced in the early 1970s.
  • The SS hurricane wind scale categorizes cyclones based on maximum sustained wind speeds at a height of 10 meters.
  • Categories range from 1 to 5, with Category 5 representing wind speeds exceeding 252 km/hour.
  • Factors like storm surge and rainfall contribute to cyclone-related damage.
  • Wind speed remains a crucial metric for assessing risk and impact.

Impact of Global Warming

  • Man-made greenhouse gas emissions have led to a warming of approximately 1.10°C since pre-industrial times.
  • This warming trend extends to ocean depths, increasing the heat content of oceans and favoring cyclone intensification.
  • Long-term data indicate a rise in the frequency of intense tropical cyclones, with each degree of warming corresponding to a 12% increase in wind speed and a 40% increase in destructive potential.

Emergence of Category 6 Cyclones

  • Recent research suggests that cyclones exceeding Category 5 intensity are becoming more frequent, with record wind speeds expected to continue rising.
  • Observations reveal that half of the Category 5 cyclones occurred in the last 17 years, with several storms surpassing the hypothetical Category 6 threshold.
  • Climate simulations predict a further increase in the annual exceedance of Category 6 thresholds, especially in regions prone to intense cyclones.
  • Given the escalation of cyclone intensity due to global warming, there is a compelling case for introducing Category 6 on the SS hurricane wind scale.
  • This additional category would raise awareness of the heightened risks posed by large cyclones and underscore the urgency of addressing climate change.

Implications for Vulnerable Regions

  • While the North Indian Ocean currently experiences fewer Category 6 storms, ongoing climate change suggests a heightened risk in the future.
  • Revisiting disaster management strategies and early warning systems is imperative to mitigate the potential impacts on lives and infrastructure in vulnerable regions.

SOURCE: https://www.thehindu.com/sci-tech/science/increasing-tropical-cyclones-of-higher-intensity-necessitates-a-new-category/article68006554.ece

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